The normal mechanisms of defense against infectious agents in the female reproductive tract are poorly understood. We propse to study the local secretory immune system. We will quantitate the number of plasma cells secreting immunoglobulins A,G, and M in the mucosae of the oviduct, uterus, cervix, and vagina of female mice during the estrus cycle, in early pregnancy, and after treatment with several ovarian hormonal regimens. Plasma cells will be identified in histological sections for light microscopy by staining with specific rabbit anti-mouse immunoglobulins, followed by peroxidase-conjugated sheep anti-rabbit immunoglobulins. We will then trace the transport of immunoglobulins A and G, and albumin as control, across the luminal and/or glandular epithelia of the above tissues by histochemical studies at intervals after i.v. administration of the labelled proteins. The proteins will be conjugated to FITC for light microscopy and to peroxidase for electron microscopic studies. Particular attention will be paid to the ultrastructural localization of peroxidase-conjugated proteins in the epithelial cells. We will also determine whether there are receptors for IgG and IgA on the basolateral membranes of uterine epithelial cells. Collagenase dissociated uterine cells would be exposed first to specific immunologulins, or albumin as control, then to rabbit anti-mouse Ig conjugated to ferritin. The number of ferritin molecules per unit length of membrane would be counted. Immunoglobulin binding during early pregnancy would be compared to that in diestrus, and binding to luminal and glandular epithelial cells would be compared. This study bears not only on the normal mechanisms of defense against infectious agents in the genital tract, but will also complement efforts to develop immunization procedures for fertility control. Scientific disciplines involved are reproductive biology, immunology and cell biology.